The Cretaceous to Eocene succession in central and south Jordan is characterised by passive
continental margin depositional sequences, which pass upward from alluvial/paralic to
carbonate shelf and pelagic ramp settings. Detailed section logging and outcrop mapping have
produced robust lithostratigraphic and lithofacies schemes that can be correlated throughout
the region and in the subsurface. These schemes are set in a sequence stratigraphic context
in relation to the evolution sedimentation on the Arabian and Levant plates. Three major
megasequences are described (Kurnub, Ajlun and Belqa), and these are further subdivided
into large-scale depositional sequences separated by regional sequence boundaries that
represent maximum flooding surfaces. There is close correspondence between maximum
flooding surfaces recording major sea-level rise with those derived for the Arabian and
Levant plates, although there are some discrepancies with the precise timing of global sealevel
fluctuations.
An upward change from braided to meandering stream fluvial environments in central
and south Jordan during the Early Cretaceous, reflects a decreasing geomorphological
gradient of the alluvial plain, declining siliciclastic sediment flux, and increased floodplain
accommodation, associated with a regional Late Albian (second-order) rise in relative sealevel.
The Late Albian to Early Cenomanian marine transgression across the coastal alluvial
plain marks a major sequence boundary. During Cenomanian to Turonian times a rimmed
carbonate-shelf was established, characterised by skeletal carbonates showing small-scale,
upward-shallowing cycles (fourth- to fifth-order parasequences) ranging from subtidal to
intertidal facies, arranged into parasequence sets. Rimmed carbonate shelf sequences pass
laterally to coeval coastal/alluvial plain facies to the south and east. Eustatic (third-order)
fluctuations in relative sea level during the Cenomanian and Early Turonian resulted in
deposition of ammonite-rich wackestones and organic-rich marls, during high sea-level
stands (maximum flooding surfaces). Progradational sabkha/salina facies passing landwards
to fluvial siliciclastics were deposited during an Early Turonian sea-level low stand, marks a
regional sequence boundary, above which a highstand carbonate platform was established.
A second-order, regional rise in sea level and marine transgression during the Early Coniacian
marks a Type 2 sequence boundary, and subsequent drowning of the rimmed carbonate
shelf by Late Coniacian times. Sedimentation during the Santonian to Maastrichtian was
characterised by a hemi-pelagic chalk-chert-phosphorite lithofacies association, deposited in
shallow to moderate water depths on a homoclinal ramp setting, although thicker coeval
sequences were deposited in extensional rifts. The marked change in sedimentation from
rimmed carbonate shelf to pelagic ramp is attributed to Neo-Tethyan mid-oceanic rifting,
tilting, intracratonic deformation and subsidence of the platform; this is reflected in changes in
biogenic productivity and ocean currents. Oceanic upwelling and high organic productivity
resulted in the deposition of phosphorite together with giant oyster banks, the latter developing
within oxygenated wave-base on the inner ramp. Chalk hardgrounds, sub-marine erosion
surfaces, and gravitational slump folds indicate depositional hiatus and tectonic instability
on the ramp. In the Early Maastrichtian, deeper-water chalk-marl, locally organic-rich, was
deposited in density-stratified, anoxic basins, that were partly fault controlled.
Pulsatory marine onlap (highstand sequences) during the Eocene is manifested in pelagic
chalk and chert with a paucity of benthic macro-fauna, indicating a highly stressed, possibly
hypersaline, and density-stratified water column. Comparison with global and regional
relative sea-level curves enable regionally induced tectonic factors (hinterland uplift and
ocean spreading) to be deduced, against a background of global sea-level rise, changing
oceanic chemistry/productivity and climatic change.

Evolution of Cretaceous to Eocene alluvial and carbonate platform sequences in central and south Jordan.

Eustacy during the Cretaceous: Its implications and importance

Late cretaceous paleogeography of northern Israel and its significance for the Levant geology

Hardgrounds and omission surfaces are rare in the predominantly pelagic
and hemi-pelagic chalk, chert and phosphorite lithofacies association that
forms the Upper Cretaceous (Coniacian to Maastrichtian) Belqa Group
succession in central Jordan However, newly-described hardgrounds of
regional extent at the base of the Dhiban Chalk Member (Campanian) in
central and south Jordan reveal a complex history of sedimentation and early
diagenesis Following drowning of the Turonian carbonate platform during
the Coniacian, the chalk-chert-phosphorite association was deposited on a
pelagic ramp in fluctuating water depths The Mujib Chalk and Dhiban Chalk
members represent high-stand sea levels, separated by a regressive, lowstand
chert-rich unit (Tafilah Member) Hardground successions can be
traced over 100 km, and show an early diagenetic history of phosphatisation
and biogenic silica lithification from opal-A to opal-CT and quartz that
resulted in penecontemporaneous chert deformation, followed by submarine
bioerosion and colonisation by corals and/or bivalves Subsequent deposition
of detrital, remanie phosphatic chalk passing up into pelagic coccolith-rich
ooze reflects a transgressive third-order sea-level rise during the Early
Campanian These events provide a time-frame for early silica diagenesis and
subsequent hardground development Regional variations in the hardground
successions and their early diagenesis are attributed to their precursor host
sediment and relative palaeogeographic position on a homoclinal ramp at the
southern margin of the Neo-Tethys Ocean

/pdf/early-diagenesis-of-late-cretaceous-chalk-chert-phosphorite-4a4rjjomuz.pdf

Early diagenesis of Late Cretaceous chalk-chert-phosphorite hardgrounds in Jordan : implications for sedimentation on a Coniacian-Campanian pelagic ramp

Fluorine occurrence in groundwater in Israel and its significance

SUMMARY

Two environments of phosphate deposition within carbonate rocks are distinguished on the basis of the relationship between phosphate content and the foraminiferal plankton/benthos (P/B) ratio in Senonian-Maastrichtian chalks of Galilee, Northern Israel:



(1) A normal marine environment of phosphate deposition during Santonian time. This environment is characterized by a low, normal P2O5 content and a positive correlation between P/B ratio and P2O5. Since it is assumed that the P/B ratio increases with the depth of the sea, it is suggested that the phosphate content in carbonate rocks can be employed as a bathymetric indicator.



(2) An “abnormal” high phosphate deposition environment, found mainly in Upper Campanian sediments and related genetically to the economic phosphorite deposits in the Negev (Central Israel). The negative correlation of P/B ratio to P2O5 is caused by a shallowing of the sea and a continuous increase in P2O5, (e.g., by upwelling currents or a terrigenous supply) throughout the Upper Campanian.

Correlation Between Phosphate Content and the Foraminiferal Plankton/benthos Ratio in Chalks (late Cretaceous, Northern Israel): Paleoenvironmental Significance?

A. Flexer

Papers

Correlation Between Phosphate Content and the Foraminiferal Plankton/benthos Ratio in Chalks (late Cretaceous, Northern Israel): Paleoenvironmental Significance?